Note 15 - Fair Values of Financial Instruments - Carrying Amount and Fair Value of Financial Instruments Included in the Consolidated Balance Sheet (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Debt securities, fair value	$ 113,041,000	$ 120,107,000
Securities - equities	15,000	19,000
Loans held for sale	75,000
Federal bank stock	5,635,000	5,790,000
Fair Value, Inputs, Level 1 [Member]
Debt securities, fair value
Securities - equities	15,000	19,000
Fair Value, Inputs, Level 2 [Member]
Debt securities, fair value	111,035,000	116,085,000
Securities - equities
Fair Value, Inputs, Level 3 [Member]
Debt securities, fair value	2,006,000	4,022,000
Securities - equities
Reported Value Measurement [Member]
Cash and cash equivalents	37,439,000	14,986,000
Interest earning time deposits	5,718,000	9,698,000
Debt securities, fair value	113,041,000	120,107,000
Securities - equities	15,000	19,000
Loans held for sale	75,000
Loans, net	800,338,000	695,348,000
Federal bank stock	5,635,000	5,790,000
Accrued interest receivable	3,786,000	2,600,000
Total	966,047,000	848,548,000
Deposits	893,627,000	787,124,000
Borrowed funds	32,050,000	28,550,000
Accrued interest payable	474,000	616,000
Total	926,151,000	816,290,000
Estimate of Fair Value Measurement [Member]
Cash and cash equivalents	37,439,000	14,986,000
Interest earning time deposits	5,718,000	9,698,000
Debt securities, fair value	113,041,000	120,107,000
Securities - equities	15,000	19,000
Loans held for sale	75,000
Loans, net	807,170,000	697,990,000
Federal bank stock
Accrued interest receivable	3,786,000	2,600,000
Total	967,244,000	845,400,000
Deposits	899,446,000	793,999,000
Borrowed funds	33,256,000	29,133,000
Accrued interest payable	474,000	616,000
Total	933,176,000	823,748,000
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	37,439,000	14,986,000
Interest earning time deposits
Debt securities, fair value
Securities - equities	15,000	19,000
Loans held for sale
Loans, net
Federal bank stock
Accrued interest receivable	52,000	78,000
Total	37,506,000	15,083,000
Deposits	705,680,000	569,357,000
Borrowed funds
Accrued interest payable	19,000	51,000
Total	705,699,000	569,408,000
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents
Interest earning time deposits	5,718,000	9,698,000
Debt securities, fair value	111,035,000	116,085,000
Securities - equities
Loans held for sale	75,000
Loans, net
Accrued interest receivable	513,000	419,000
Total	117,341,000	126,202,000
Deposits	193,766,000	224,642,000
Borrowed funds	33,256,000	29,133,000
Accrued interest payable	455,000	565,000
Total	227,477,000	254,340,000
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents
Interest earning time deposits
Debt securities, fair value	2,006,000	4,022,000
Securities - equities
Loans held for sale
Loans, net	807,170,000	697,990,000
Federal bank stock
Accrued interest receivable	3,221,000	2,103,000
Total	812,397,000	704,115,000
Deposits
Borrowed funds
Accrued interest payable
Total